No one had ever compiled more total yards in his first N.F.L. game, and according to Pro Football Reference, no one in the last 36 years had rushed for more in his debut than Hunt’s 148. Ergo, Hunt, a third-round pick from Toledo, will go on to do many, many great things — the best things.

One game into these brutal four months of attrition known as the N.F.L. season is the perfect time to overreact and project — to enjoy Hunt’s being on pace for 2,368 rushing yards, to parse that small sample and savor it before all that tantalizing turns to tease.

In the coming weeks, the elite of this rookie class will emerge, and it may not even include the best from Sunday — or, in the case of Vikings running back Dalvin Cook, Monday night. Remember: Just last year, in the Cowboys’ opener, Dak Prescott completed 55.6 percent of his passes and Ezekiel Elliott averaged just 2.55 yards on 20 carries. Prescott went on to smash the rookie record for quarterback rating (104.9), throwing 23 touchdowns to 4 interceptions, while Elliott would lead the N.F.L. in rushing with 1,631 yards.

Quarterback

Optimism, that rarest of commodities among the football-loving denizens of northeast Ohio, abounded on Sunday, even with Cleveland losing by 21-18 to the hated Steelers. Unlike many of his predecessors, the starting quarterback, DeShone Kizer, demonstrated a remarkable capacity for not offering fans reason to cry, drink or both.

DeShone Kizer completed 20 of 30 attempts for 222 yards,

Jason Miller / Getty Images

Against what should be one of the N.F.L.’s best defenses, Kizer completed 20 of 30 attempts for 222 yards, throwing for one touchdown and an interception, while also running for a score. He made some sharp throws but also some ill-advised ones, looked downfield often but also holding onto the ball too long, getting sacked seven times.

The Browns’ quest for a savior, loaded with failed draft picks and deep into its third decade, brought them to Kizer, strong-armed and mobile, whom they took in the second round out of Notre Dame after bypassing the consensus top three quarterbacks — Mitchell Trubisky, Patrick Mahomes and Deshaun Watson.

Only Drew Bledsoe, Matthew Stafford and Jameis Winston were younger than or as young as Kizer, 21, when they debuted. All three were chosen first overall, but all three had also inspired enough confidence to earn the starting job at that age. So far, if nothing else, Kizer has done that, too.

Another team with entrenched quarterback problems, the Texans, have long managed to obscure them with their outstanding defense. But let the record show that for the fifth consecutive season they opened with a new starter, and this one, Tom Savage, after Jacksonville sacked him six times, lasted all of one half. In came Deshaun Watson, who capped a 14-play drive, extended by penalties, with a touchdown to DeAndre Hopkins.

Though Watson did show a knack for extending plays, that touchdown was his highlight. He finished 12 of 23 for 102 yards, averaging a meager 4.4 yards per attempt, and lost a fumble. His potential compelled Houston to trade up to select him in April, with the 12th pick, and the Texans hoped to ease him in this season and start him next. Right, well, anyway.

Their coach, Bill O’Brien, has a sordid history of changing quarterbacks — Brian Hoyer, Ryan Mallett, Brock Osweiler, et al. — and he will have an interesting decision to make in this short week, with the Texans playing Thursday night at Cincinnati. If O’Brien bets on promise, Kizer won’t be the only rookie starting in Week 2.

Running Back

Leonard Fournette may yet live to regret his preseason claim that the N.F.L. is “really easy,” but not this week. Ruthless between the tackles, Fournette pounded one of the league’s more formidable defenses, tagging Houston for 100 yards — many after contact — and a touchdown on 4th and goal from the Texans’ 1. On that play, he rammed into linebacker Brian Cushing to extend over the goal line. On another, he bowled over safety Andre Hal.

Leonard Fournette tagged Houston for 100 yards — many after contact — and a touchdown on 4th and goal from the Texans’ 1.

David J. Phillip / Associated Press

The Jaguars, for all of their recent struggles, have a rich lineage of running backs, and only Fournette, the team’s first-round pick out of L.S.U. — not Fred Taylor, not Maurice Jones-Drew — ran for 100 yards in his first N.F.L. game. His importance is likely only to increase with the team’s top receiver, Allen Robinson, out indefinitely after tearing a knee ligament.

Tarik Cohen, Fournette’s opposite in many ways — build, pedigree, running style — enthralled all the same on Sunday at Soldier Field in Chicago. Dubbed the Human Joystick, the 5-foot-6 Cohen juked, feinted and dipped past Atlanta defenders en route to rushing for 66 yards, catching eight passes for 47 and a touchdown and returning three punts for 45. In just one game, Cohen, a fourth-round pick from North Carolina A&T, established himself not only as the Bears’ most dangerous offensive threat — their version of Darren Sproles — but also as one of the more exciting rookies in the league.

Wide Receiver

From watching the Detroit Lions practice in early August, the former star receiver Chad Ochocinco came away with one overarching impression: their rookie receiver Kenny Golladay, he posted on Twitter, had the “IT Factor.” A third-round pick from Northern Illinois, Golladay showcased his size and catch radius in the preseason, and again on Sunday, when he caught four passes — including two beautiful touchdowns — in the Lions’ 35-23 victory against Arizona.

On his first score, the 6-foot-4 Golladay reached over Cardinals cornerback Justin Bethel. On his second, a 45-yarder, Golladay zipped past two defenders to catch the ball while diving toward the goal line. In Golden Tate and Marvin Jones, the Lions have reliable and potent intermediate options. But Golladay, however callow, offers a deep presence that Detroit has lacked since Calvin Johnson retired.

Outside Linebacker

The best rookie edge-rusher at FirstEnergy Stadium in Cleveland on Sunday was not the No. 1 overall pick Myles Garrett, inactive for the Browns with a sprained ankle, but a nuisance with a most recognizable surname.

T.J. Watt, left, became the first player to have at least two sacks and an interception on the league’s opening weekend since 1982.

Those two sacks are an extension of T.J.’s final season at Wisconsin, where he amassed 11.5, most in the Big 10. Harassing the quarterback is what he is supposed to do. But his interception? It came more than 10 yards downfield, after dropping into coverage, on a leap to catch the high pass. Not many who have Watt’s build — he is listed at 6-feet-4 and 252 pounds can make that play. But not many have his genes, either.